The present invention relates to machines having a hydrostatic transmission, such as a tractor, and more particularly, to a combined foot brake and parking brake mechanism for the machine which is interconnected with the hydrostatic transmission shift arm.
It is conventional to provide tractors and similar machines with hydrostatic transmissions for controlling the speed, direction, and pulling power of the tractor. The transmission is provided with a rotatable shift arm or lever which may be rotated in one direction for forward motion of the tractor and in the opposite direction for rearward or reverse motion. The speed of the tractor is proportional to the rotation of the shift arm while the tractor engine is operated at a speed set by a conventional throttle device.
Tractors of this type generally do not include a parking brake or brake pedal. The tractor is held on an incline by slightly advancing the hydrostatic transmission shift arm in forward or reverse. When the transmission shift arm is set at neutral, the tractor may roll down an incline. If the tractor is provided with a parking brake, the brake may be accidentally left engaged when the hydrostatic transmission is actuated into forward or reverse, wearing or possibly damaging the brake.
This problem is solved in the combined foot brake and parking brake mechanism of this invention, by functionally connecting the parking brake mechanism to the transmission shift arm, such that the parking brake cannot be engaged unless the transmission shift arm is in its neutral position. Further, the parking brake mechanism must be released before the hydrostatic transmission can be acutated by the shift arm from neutral into forward or reverse. The combined foot brake and parking brake mechanism of this invention is relatively simple and mechanically actuated to reduce the chances of failure.